The conservation of clean water is of increasing concern. This concern is most clearly felt in areas of the World such as Africa, the Middle East and Australia, where the environment can be harsh. However, even in countries with a plentiful supply of water, domestic water must be stored in reservoirs and it must be treated to be fit for human consumption.
In areas where water is in plentiful supply, the levels of wasted water are high. On an individual level waste may not be huge, but the accumulated wasted water from all the users represents a large amount of clean water that is simply fed down the drain.
One particular source of waste occurs every morning when it takes time for the hot water to come through the water pipes to the hot tap. As a result the first user at each tap usually turns on the tap until the water runs hot. In this way, in any one city on any one morning, millions of liters of clean water can be wasted.
Various solutions to the above problem have be put forward. However, all of the offered solutions have disadvantages, which, have prevented their wide-scale adoption.
Canadian Patent No 2252350 describes a water supply system wherein water that is either too hot or too cold is prevented from exiting the system via an open tap. The system prevents the wastage of water discussed above by diverting water of the wrong temperature back around the system until the water reaching the chosen tap is the correct temperature.
One of the main problems with the above system is that it requires a complete re-plumbing of the water supply system, including the pipes and taps. This may not be a huge issue with new build properties, but it can be prohibitive in older properties, where the total water savings by the individual property do not warrant the plumbing costs. Furthermore, the nature of the valve system used in Canadian Patent No 2252350 is such that new bathroom furniture (e.g. taps, shower-heads, etc.) must be fitted also. This further increases the costs involved as well as limiting the level of aesthetic choice available to the owners of the property.
Another solution is offered by the “demand system”, this system uses the same principal as is used for central heating, it has the hot water being constantly pumped around the water pipes, so when a faucet is opened the passing hot water is there ready for use, this system requires quite an alteration to the plumbing, also needs a supply of electricity for the pump and switches and a water pump that is expensive to buy and run, it also needs the returned and cooled water to be constantly re-heated which is a very uneconomical operation, and is therefore both expensive to install and run, and uses large amounts of valuable energy to constantly re-heat the circulating water. The actual system is extremely expensive and the cost is not recoverable from saved water bills, so is in very little use, and rarely seen on the market. U.S. Pat. No. 4,554,688 is an example of this form of water supply system.
U.S. Pat. No. 5,165,456 describes a more basic solution to the above-mentioned problem with the previously wasted water being diverted to a portable water tank. Whilst such invention provides a solution to the above problem without the disadvantages of the Canadian patent, the invention is impractical and intrusive. The constant need for the user to lift and move the water storage tank would inevitably lead to the system being abandoned.
International PCT Application No. AU2004/000415 discloses a water recovery system that addresses the above identified problem by providing a valve assembly that can be fitted into the plumbing upstream of a tap outlet. The valve assembly ensures that only water that is above a predetermined temperature reaches the tap for discharge. The water that is not above the predetermined temperature is diverted to a water storage means, such as a water tank. The valve assembly is activated by a drop in water pressure at the tap outlet, which occurs when the tap is turned on. This avoids the need for any sort of mechanical connection between the valve assembly and the tap outlet, as was described in UK Application No. 0520317.9.
Although PCT/AU2004/000415 provides an effective solution to the above identified problems the disclosed valve assembly requires expensive and sometimes unreliable components. The use of large ceramic components for example, which require a high level of precision, means that the cost of manufacturing the valve assembly can prohibitive. Also the use of the sometimes unreliable diaphragm in the valve assembly can lead to additional repair costs for the user.
In view of the above solutions to the identified water wastage problem, and the disadvantages thereof, there is a need for water saving system that has minimised hurdles to adoption, so that the average consumer will not be discouraged from adopting a water saving system.